1. Field of the Invention
The present invention relates to ventilating apparatus. It particularly relates to an improvement in ventilating apparatus which works to discharge and ventilate contaminated indoor air in indoor living space such as an automobile room, a room of a building and the like, to the outdoors.
2. Description of Related Art
An automobile traveling on a bad road like the desert requires a high degree of air-tightness in order to prevent sand and the like from coming into the automobile. However, if the air-tightness is simply increased, passengers still suffer from an unpleasant feeling due to a sudden pressure increase in the automobile when a door is closed. Accordingly, automobiles are equipped with ventilating apparatus which flows air only in one direction, namely from inside of the automobile to the outdoors.
Conventional ventilating apparatus comprises a duct including an indoor air inlet port for receiving indoor air of an automobile room, an indoor air outlet port for discharging the indoor air to an outside of the automobile and a one-way valve, disposed on the indoor air outlet port, for opening the indoor air outlet port only when discharging the indoor air to the outside of the automobile room.
The one-way valve is connected to a wall surface forming the indoor air outlet port at one end thereof, and another end of the one-way valve is made swingable around a connection i.e., around the one end thereof. The one-way valve usually closes the indoor air outlet port by itself with its own weight. When a pressure difference between the inside and the outside of the automobile, for instance, a negative pressure generating and acting on the one-way valve during automobile traveling, reaches a magnitude overcoming the weight of the one-way valve, the other end of the one-way valve swings in a direction getting away from the indoor air outlet port, thereby opening the indoor air outlet port. Such a conventional technology is disclosed in Japanese Unexamined Patent Publication (KOKAI) No. 63221/1984 and Japanese Examined Utility Model Publication (KOKOKU) No. 9130/1987.
In the conventional ventilating apparatus, it has been required to discharge indoor air quickly when the indoor air is contaminated with cigarette smoke and the like. Accordingly, the weight of the one-way valve has been reduced in order to open the indoor air outlet port with a small pressure difference with ease and discharge the contaminated air in the automobile room efficiently. Nevertheless, when the weight of the one-way valve is reduced, deteriorated sealing occurs when the one-way valve closes the indoor air outlet opening. As a result, it is hard to close the indoor air outlet port securely with having a reduced weight one-way valve. Hence, contaminated outdoor air, or outdoor air containing fine sand, dust, smoke and the like, intrudes into the automobile room through clearances between the one-way valve and the indoor air outlet port.